CONTOUR Team Ends Contact Attempts
December 20, 2002
Efforts to communicate with CONTOUR ended shortly after noon today without a
signal from the NASA spacecraft, and mission managers say they will not try
to contact the silent probe again.
"Given what we suspected about CONTOUR's condition, and that we haven't
received a signal after several contact attempts, we don't believe the
spacecraft is recoverable," says Edward Reynolds, CONTOUR project manager at
the Johns Hopkins Applied Physics Laboratory (APL), which manages the
CONTOUR mission for NASA. "At this point the project will recommend to NASA
that efforts to contact the spacecraft should end, and the project will
formally close down."
Launched July 3, 2002, CONTOUR fell silent after firing its onboard STAR 30
solid-propellant rocket motor on Aug. 15, during a maneuver to boost the
spacecraft from a parking orbit around Earth. Ground-based telescope images
taken shortly after showed three objects near CONTOUR's expected path,
indicating CONTOUR had broken up near the scheduled end of the burn. Without
data from the spacecraft, however, the mission team could only infer whether
CONTOUR was fatally damaged. Attempts to contact the craft in the weeks
after the anomaly proved unsuccessful.
(A NASA-appointed panel, led by NASA Chief Engineer Theron M. Bradley Jr.,
is investigating potential causes of the mishap.)
CONTOUR team members planned the final contact effort for this week, when
they believed the spacecraft's multidirectional pancake beam antenna would
be better positioned to receive signals from Earth. On Dec. 17, and again
this morning, mission operators at APL sent several "transmit" commands
through NASA's Deep Space Network (DSN) antennas toward the suspected
location of the largest piece, thought to be the bulk of the spacecraft,
about 42.5 million miles (68 million kilometers) from Earth. After 16 total
hours of sending and watching, no signal came back.
Reynolds says the silence almost certainly means the end of a mission and a
spacecraft that, up until Aug. 15, was operating wonderfully. In the six
weeks after launch, mission operators and navigators guided the
solar-powered craft through 23 propulsive maneuvers, positioning it
precisely for the 50-second rocket burn that was to send CONTOUR toward
close-up encounters with at least two comets. Several technical aspects of
CONTOUR itself - such as an innovative non-coherent navigation system - met
controllers' high expectations and could find places in future spacecraft
designs. Also, new developments within CONTOUR's imaging instruments are
being incorporated into upcoming missions to Mercury, Mars and Pluto.
"A lot of people worked hard to build CONTOUR and prepare for this mission,
and we're deeply disappointed that it didn't work out," Reynolds says. "The
interest in CONTOUR was remarkable; people from around the world told us how
excited they were about the chance to learn more about comets than any
mission had taught before. We hope this team will have another opportunity
to make that happen."
CONTOUR is a NASA Discovery Program mission to explore comet diversity. The
Johns Hopkins University Applied Physics Laboratory, Laurel, Md., manages
the mission for NASA and built the CONTOUR spacecraft. Dr. Joseph Veverka,
of Cornell University, Ithaca, N.Y., is CONTOUR's principal investigator.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Deep Space
Network.